Texas cedarwood oil, a material having a high thujopsene content is a natural product of "Texas cedarwood" trees otherwise properly known as Juniperus Mexicana. The oil of Juniperus Mexicana ranks among one of the more highly utilized essential oils and it enjoys the steady interest of perfumers and an increasing interest of the manufacturers of aromatic chemicals. Juniperus Mexicana grows abundantly in the southwestern parts of Texas, toward the south in Mexico and Central America. The cedarwood oil is generally steam distilled from the heartwood of this tree which is filled substantially exclusively for the purpose of producing the essential oil. The crude oil is a viscous liquid having an odor which is pleasant, sweet woody jet somewhat tar-like or cade-like and smoky. On drying it becomes increasingly balsamic-sweet and shows a great tenacity with a uniform sweet, woody dry-out. The rectified oil of Juniperus Mexicana is pale yellow to colorless. Its odor is less tar-like, less cade-like or smoky than that of the crude oil. The dry-out is clean, sweet, woody with a typical "pencil sharpener" odor. It is customary to fractionate the crude oil during the redistillation according to Arctander, "Perfume and Flavor Materials of Natural Origin" at column 144 and 145, a "light" fraction consists mainly of sesquiterpenes and it presents the dry-woody part of the cedarwood notes. The "heavy" fractions consist mainly of cedrol. These sesquiterpene alcohols can be isolated in a more or less pure state from the resulting product. They are solid materials of weak, but very pleasant, woody-balsamic aromas.
In an effort to conserve growing areas for Juniperus Mexicana, it has become commercially feasible to cause the Juniperus Mexicana to yield a larger quantity of cedarwood oil having the same chemical constituency as that yielded ordinarily by Juniperus Mexicana.
Accordingly, the present invention relates to a method of chemically increasing the amount of thujopsene-containing cedarwood oil extractable from the wood of Juniperus Mexicana by treating living growing Juniperus Mexicana with solutions containing, but not necessarily limited to, bipyridylium salts, continuing to permit the Juniperus Mexicana to grow for a period of at least two months and then cutting all or sections of said Juniperus Mexicana and extracting the resulting high thujopsene-containing cedarwood oil from the wood.
The prior art has shown that such bipyridylium compounds can induce increased production of materials such as oleoresin materials. Thus, U.S. Pat. No. 4,201,566 issued May 6, 1980, the disclosure of which is incorporated by reference herein, discloses a method of chemically increasing the amount of extractable oleoresinous and tall oil material from pine wood by treating severed living portions of pine trees with a dilute solution of a bipyridylium salt and storing the treated wood for a period of approximately 3-30 days. It is stated in said U.S. Pat. No. 4,201,566 that the living portions of pine trees may be in the form of tree boles from felled trees, stems, twigs, roots or needles and chips, shavings or sawdust thereof.
It has also been shown that bipyridylium compounds can induce increased production of oleoresin material in living, standing pine trees. Thus, Roberts, et al U.S. Pat. No. 3,839,823 issued Oct. 8, 1974, the specification of which is incorporated herein by reference, states that the living tree may typically be treated with a chemical solution by applying the solution to a treatment site on the living tree. Treatment sites are prepared by various methods such as: removing a small section of bark to expose sapwood, making an ax cut deep enough to expose sapwood or by boring a small, downwardly sloping hole into the sapwood. Also pertinent is U.S. Pat. No. 2,971,159, the specification of which is incorporated by reference herein. It is taught in said U.S. Pat. Nos. 3,839,823 and 4,201,566 that the purpose of these treatment sites is to permit the chemical solution, e.g. the solution of bipyridylium salts, to be adsorbed into the living cells of the tree. Once applied to a living tree, the chemical is mobile and may be carried to distant areas within the tree. The chemical, once absorbed into the living cells of the bark and wood (xylem), induces the cells to produce and secrete copious amounts of oleoresin into other adjacent wood fibers until the wood becomes resin or "pitch" soaked. At least some of the carbon necessary to carry out the synthesis of the oleoresins comes from sugars and other substrates ultimately produced by photosynthesis in the leaves of the living tree. In this manner, the oleoresin production of a living tree may, after a period of from 6-12 months following treatment, be increased manyfold. Following the treatment period, the tree must be felled and the heavy "pitch" soaked portions are then transported to an extraction plant where the oleoresins and tall oil components are extracted from the wood using methods well known in the art.
More specifically, U.S. Pat. No. 4,176,495, issued Dec. 4, 1979, the specification of which is incorporated by reference herein, discloses an apparatus and method for drilling a borehole, into the sapwood of a tree and injecting such chemical solution as bipyridylium salts into the borehole, preferably during withdrawal of the drill bit, including facilities for supplying a liquid through a passageway within the bit and facilities for injecting a quantity of liquid proportional to the volume of the borehole and allocated simultaneously with and in response to progression of the drill bit into the borehole as the drill bit is being withdrawn therefrom.
Bipyridylium salts have been used and taught to be useful in the prior art for lightwood formation in red pine and northwest conifers as shown in:
(a) Wroblewska, et al "Lightwood Formation in Red Pine Treated With Paraquat" Wood Science, Volume 10, Number 1, July 1977, page 1. PA1 (b) Lightwood et al "Paraquat Treatment of Northwest Conifers for Lighwood Induction" Wood Science, Volume 10, Number 1, July 1977, page 28. PA1 (c) Roberts and Peters "Chemically Inducing Lightwood Formation in Southern Pines" Forest Products Journal, Volume 27, Number 6, June 1977, page 28. PA1 (d) Drew and Roberts "Developments in Paraquat Treatment of Trees to Induce Lightwood Formation" Forest Products Journal, Volume 27, Number 7, July 1977, page 43. PA1 (e) Kiatgrajai, et al "Attempt to Induce Lightwood in Balsam Fir and Tamarack by Treating with Paraquat" Wood Science, Volume 9, Number 1, July 1976, Page 31. PA1 (a) first steam distilling the resultant green or aged cedarwood chips and condensing the overhead distillate thereby forming two liquid phases; an aqueous phase and an organic phase; PA1 (b) separating the aqueous phase from the organic phase; PA1 (c) optionally extracting the aqueous phase with an organic solvent such as diethylether to form a solvent extract; PA1 (d) optionally evaporating the solvent extract and recycling the solvent; PA1 (e) optionally combining the resulting residue with the steam distilled organic oil phase; PA1 (f) optionally fractionally distilling the resultant combined organic phase or separated organic phase (if no extraction takes place) to yield a rectified cedarwood oil in high yield.
In addition, other processes for increasing oleoresin synthesis in pinus species are set forth in, for example, Wolter, et al., U.S. Pat. No. 4,203,253 issued May 20, 1980, wherein it is disclosed that stimulation of oleoresin production associated with living cells can be chemically induced with dilute systemic application of ethylene or ethylene-releasing compounds taken in combination with bipyridylium salts. Disclosed is the fact that one such ethylene-releasing compound is 2-chloroethylphosphonic acid. It is further stated in U.S. Pat. No. 4,203,253, the specification of which is incorporated by reference herein, that oleoresin production can be accomplished by using ethylene-releasing chemicals in combination with the bipyridylium salts, diquat or paraquat.
A specifically disclosed technique for preparing a treatment site on the hole of a conifer useful in conjunction with the instant application for U.S. Letters Patent is set forth in U.S. Pat. No. 3,971,159 issued on July 27, 1976, the specification of which is incorporated by reference herein.